Title: Improving the Evaluation of Therapist Adherence to Multi-systemic Therapy with Ethnically Diverse, Adolescent Drug Offenders. ABSTRACT: Treatment fidelity is of central importance in efforts to disseminate empirically-supported treatments to "real-world" settings. Unfortunately, the limited availability of valid measures of treatment fidelity limits the ability to evaluate and maintain treatment adherence in community mental health settings. Since African American youth tend to be over-represented among those with serious mental health problems, the dearth of effective treatments and valid methods for evaluating fidelity to such treatments disproportionately effects them. This study proposes to develop further an existing measure of treatment fidelity, the Multisystemic Therapy Adherence Measure, which measures therapist adherence to the Multi-systemic Therapy (MST; Henggeler; Schoenwald, Borduin, Rowland, & Cunningham, 1998) treatment protocol. A recently funded randomized trial funded by NIAAA and NIDA provides an opportunity to build on existing psychometric work with the MST Adherence measure to enhance the potential for transporting MST to community treatment settings. This study has two primary aims related to the refinement and validation of the original MST adherence measure. First, this application proposes to develop an adherence measure that (1) taps the 9 principles which operationalize MST with greater specificity than the previous measure, and (2) indexes additional dimensions that differentiate MST from traditional mental health treatment for substance abuse problems in youth. The second aim is to examine the utility of treatment adherence in predicting short- and long-term treatment outcomes in a multi-ethnic sample of substance abusing juvenile offenders and evaluate whether adherence to the MST treatment protocol is equally predictive of outcomes for African American and Caucasian youth and families Since MST has proven to be an effective treatment for African American and Caucasian youth and families. Since MST has proven to be an effective treatment for African American offenders, the development of an inexpensive yet valid measure for facilitating treatment adherence to MST in "real-world" settings should aid in improving the quality of mental health care for African American youth. If the measure is shown to be a valid index of treatment adherence, a proposal for a randomized trial will be developed to study the effectiveness of this measure as a time- and cost-efficient feedback mechanism for MST therapists and clinical supervisors in maintaining adherence to the MST treatment protocol.